Guillaume de L'Isle (1675-1726) was a cartographer and the Premier Geographer to the King in France beginning in 1718. His family played a significant part in the world of French cartography in the eighteenth century. At age 9, he drew his first map and at age 27 he became a member of the Académie Royale des Sciences. He studied under Jacques Cassini, acquiring knowledge in both mathematics and astronomy. Due to his academic background and his "critical approach to the maps of his predecessors" he became known as the first "scientific cartographer" (Moreland and Bannister, 132). Among his works are "Globe, map of the world and the four continents" (1700), "Atlas de Géographie" (1700-12), "Mississippi" (1701), "Carte du Mexique et de la Floride…" (c.a. 1703), "Carte de la Louisiane et du Mississippi" (1718) and posthumously, "Atlas Noveau" (1730 and later). Following his death, his widow, Marie Angélique de L'Isle took up the business with a partner, Philippe Buache (Tooley 395; Moreland and Bannister, 131-2).

This particular map was first published in De L'Isle's "Atlas de Geographie" in 1727 by his wife, Marie Angélique de L'Isle. It was later reprinted in 1745 by Philippe Buache, Marie's son-in-law, business partner, and following her death, the inheritor of Guillaume de L'Isle's map plates. The map follows the geographic information known of this part of Africa current to the time period (Betz, 498). For instance, the source of the Gambia River is erroneously shown as a mythical lake, Lac de Sapert. Timbuktu is shown slightly further south of its actual location. The map's emphasis on French claims in Africa is significant as it exemplifies the rupture in Portuguese domination of western Africa. Also of note, the course of the Niger River has been confused with the Senegal River. The map's value lies in its detailed naming of places along the coastline. Its lack of detail beyond the coastline is evidence of the lack of exploration of much of Africa at this time period (Delaney, "To the Mountains of the Moon: Mapping African Exploration, 1541-1880.")

Source(s):

Betz, Richard L. "The Mapping of Africa: A Cartobibliography of Printed Maps of the African Continent to 1700." 't Goy Houten: Hes & de Graaf, 2007.